Pipelines are generally known to transport fluids (liquids or gases) over a physical distance within the internal cavities of the constituent individual pipe sections. In order to test the pipeline or to make occasional repairs or alterations to the pipeline, it is disruptive and/or undesirable to shut off the flow of fluid through the pipeline during the period of testing or repair. Rather, a plumbing technician will utilize a test plug, having a diameter similar to the inner diameter of the pipeline, to wholly or partially obstruct the pipeline. Once obstructed, testing or repairs may be performed downstream from the location where the test plug is obstructing the pipeline.
In certain applications involving a pipeline transporting fluids at high backflow pressures, there is an increased difficulty and risk with wholly or partially obstructing the pipeline. Namely, due to the higher pressure in the pipeline, traditional test plugs are at a heightened risk for failure resulting from the higher load it must withstand. The test plug could experience an “application failure” wherein the plug does not maintain its position within the pipeline (i.e., it is prone to sliding). Alternatively, the test plug could experience “design failure”, where the materials of the plug will separate from one another. Depending on the type of design failure, damage to the pipeline and/or injuries to the plumbing technician are possible. Existing test plugs are insufficient for use in high backflow pressure pipelines because they are structurally unsound and prone to failure.
Therefore, there is a need for a test plug that is structurally adapted for use with high pressure pipeline, particularly around 150 pounds per square inch (psi). There is further a need for a test plug that can adequately be inflated to a high internal pressure and maintain structural integrity such that it may be used in a high backflow pressure pipeline.
The present invention provides a high pressure plug capable of withstanding increased loads and forces found in higher backflow pressure pipelines. In particular, the invention relates to a unique structure for a high pressure test plug that provides this capability. The invention is further capable of sustaining a sufficiently high internal pressure so as to be capable of use in these high backflow pressure pipelines, while also maintaining its structural integrity to due to a robust design.
The high pressure test plugs of the invention may be multi-size test plugs which are constructed and arranged to be inflated and used to seal interior portions of pipelines, having a specified diameter range, for testing, repair, and construction purposes. In particular, the high pressure test plugs of the invention may be expandable, multi-size high pressure test plugs for use in pipelines of various ranges, such as, for example, 4-8 inch inner-diameter pipe ranges, 8-12 inch inner-diameter pipe ranges, 12-16 inch inner-diameter pipe ranges, 20-26 inch inner-diameter pipe ranges, and 26-32 inch inner-diameter. The high pressure test plugs of the invention are preferably constructed of layered and reinforced elastomeric materials, metal endplates, metal rings, and an inflation member. The high pressure test plugs may further include a high pressure resistant flow-through conduit that is capable of creating a bypass through the high pressure test plug capable of withstanding the high inflation pressure within a chamber of the test plug.